An exhaust system conducts hot exhaust gases generated by an engine through various exhaust components to reduce emissions and control noise. The exhaust system includes a diesel particulate filter (DPF) that is configured to remove particulate contaminates from exhaust gas flow prior to the exhaust gases entering downstream exhaust system components. In one known configuration, the exhaust system includes an injection system with a doser that injects a reducing agent into the exhaust gases downstream of the DPF and upstream of a selective catalytic reduction (SCR) catalyst. A mixer is positioned upstream of the SCR catalyst and mixes engine exhaust gases and products of urea transformation. The doser is mounted to an outer peripheral surface of the mixer.
In one known configuration, the SCR catalyst and mixer are assembled as a first module having a mixer inlet and a SCR catalyst outlet, and the DPF is assembled as a second module having a DPF inlet and DPF outlet. The first and second modules are connected to each other via the DPF outlet and the mixer inlet. Packaging constraints in different vehicle applications require the first and second modules to be oriented at many different positions relative to each other. The inlet and outlets to the modules have to be re-configured to accommodate these different mounting orientations, which is time consuming and increases manufacturing costs via part proliferation.
Further, it is important that the mixer be able to thoroughly mix the injected fluid with the exhaust gases. As such, the mixer inlet must be configured such that exhaust gases are effectively directed into the mixer in each of the various mounting configurations.